ML20215M571

Application for Amend to License NPF-1,consisting of License Change Application 145,changing Tech Spec Sections 2.2 & 3.3 Re Steam Generator lo-lo Level & Pressurizer low-pressure Reactor Trip Setpoints

ML20215M571
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	10/08/1986
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:
Shared Package
ML20215M557	List: ML20215M556 ML20215M571 ML20215M597
References
TAC-63462, NUDOCS 8611030035
Download: ML20215M571 (6)

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PORTLAND GENERAL ELECTRIC COMPANY EUGENE WATER & ELECTRIC BOARD AND PACIFIC POWER & LIGHT COMPANY Operating License NPF-1 Docket 50-344 License Change Application 145 This License Change Application requests changes be made to the Trojan Technical Specification Section 2.2 and Section 3.3, regarding steam generator low-low level and pressurizer low-pressure reactor trip setpoints, Appendix A to Operating License NPF-1 for the Trojan Nuclear Plant.

PORTLAND GENERAL ELECTRIC COMPANY By Bart D. Withers Vice President Nuclear Subscribed and sworn to before me this 28th day of October 1986.

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Notary Public of Oregod

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My Commission Expires:

8611030035 861028 PDR ADOCK 05000344 P

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,a UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of

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PORTLAND GENERAL ELECTRIC COMPANY,

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Docket 50-344 THE CITY OF EUSENE, OREGON, AND

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Operating License NPF-1 PACIPIC POWER & LICHT COMPANY

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(TROJAN NUCLEAR PLANT)

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CERTIFICATE OF SERVICE I hereby certify that copies of License Change Application 145 to the Operating License for Trojan Nuclear Plant, dated October 28, 1986, have been served on the following by hand delivery or by deposit in the United States mail, first class, this 28th day of October 1986:

Mr. Lynn Frank, Director State of Oregon Department of Energy 625 Marion St NE Salem OR 97310 Mr. Michael J. Sykes Chairman of County Commissioners Columbia County Courthouse St. Helens OR 97051 t;- - - =

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. Zimmerman, Manager c ear Regulation Branch c ar Safety & Regulation Subscribed and sworn to before me this 28th day of October 1986.

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Notary Public of Orego g s_ u /

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LCA 145 Attachment A Page 1 of 4 Reason for Change The Trojan Updated Final Safety Analysis Report (UFSAR) and Technical Specifications reflect steam generator low-low level reactor trip and pressurizer low-pressure safety injection setpoints established by the original plant design.

Interim setpoints have been in use for several years to account for additional instrument inaccuracies that became known subsequent to plant startup. Reference les heating effects and Barton transmitter defect notifications were major contributors to these increased inaccuracies.

Subsequent improvements to the Barton transmitters, plus insulation of reference legs on the steam generator level instruments, have resulted in reduced inaccuracies and thus reduced setpoints and allowable values.

liowever, those values still remain greater than those cited in the T/S.

Reference 1 committed to revise the T/S values once the improvements noted above were complete.

Description of Change New setpoints and allowable values have been calculated for the steam generator low-low water level reactor trip and pressurizer low-pressure safety injection. They are based upon the following improvements provided by Barton for the Model 763 and 764 transmitters:

1.

Elimination of thermal repeatability errors and LOCA thermal errors.

2.

Elimination of negative shift errors.

3.

Use of Barton-supplied environmental allowance value of 5.59 percent of span, based on their evaluation of qualification results against Trojan-specific LOCA profile for temperatures and PGE's conclusion that other synergistic effcets are not significant in the interval of concern.

The causes of the thermal non-repeatability errors were identified as a leakage path from the circuit to case ground through the zero and span potentiometers, and incorrect manufacturing methodology used during the temperature compensation process. The corrective actions were the addition of isolation washers between the potentiometer mounting bracket and the potentiometers to isolate them from case ground, and revision to the temperature compensation procedures. The corrective actions have been implemented at Barton and all transmitters shipped after January 1, 1983 meet the original published performance specifications.

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.i LCA 145 Attachment A Page 2 of 4 4

The negative shift errors were the results of the combined creep of the link wire connecting the pressure sensing bourbon tube with the strain gauge beam and the link wire attachment material. In addition to correcting the creep problem, changes have been made to the method of mounting and controlling the amount of deflection of the strain gauge beam, and to the location of an insulating pad for the termination of the lead wires of the strain gauge. Subsecuent testing has shown the above

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changes result in performance within srecification limits. Instruments delivered after the defect identification incorporate the changes.

In addition, increased accuracy of the steam generator low-low level reactor trip, due to insulation of steam generator level detector reference less in l

1985, was incorporated into the same calculation.

Resultant chango from T/S Tables 2.2-1 and 3.3-4 and interim values are:

Old T/S New T/S Setpoint Allowable Interim Setpoint Allowable

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Steam Generator Low-Low

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Level Reactor Trip (%)

15 14 120 111 110 1

Pressurizer Low Pressure Safety Injection (psig) 11765 11755 11831 11766 11759 Safety Evaluation Changes are to be made to Technical Specification Section 2.0, Table 2.2-1 and associated bases and Section 3.0, Table 3.3-4.

Prior to the 1986 refueling outage Trojan operated with conservative interim setpoints (Reference 1) based on the Westinghouse Setpoint i

Study and Barton Defect Notifications for Barton Transmitters, Models 763 and 764. PGE calculated the new setpoints for the replacement transmitters based upon reference leg insulation and transmitter

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improvements provided by ITT Barton. The Trojan Safety Analysis assumes a setpoint of 4 percent for the steam generator low-low level trip and 1755 psig for the pressurizer low-pressure safety injection. The new Technical Specification limits ensure these assumed values will not be exceeded. The new limits take into consideration instrument error, circuit loop error, and environmental qualification of instrumentation.

i These new setpoints are closer to those already licensed in the Technical Specification yet provide the margin necessary to ensure Plant protection consistent with the FSAR analyses.

In addition, they provide greater flexibility for transient conditions, thereby minimizing the likelihood of i

inadvertent protective action and challenges to the Plant safety systems.

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4 LCA 145 Attachment A Page 3 of 4 The Barton transmitter replacement constitutes substitution of func-tionally equivalent components with less susceptibility to environmental conditions. Other than changing calibration setpoints, Plant peccedures are not affected. There is no reduction in safety margins. Thus, the setpoint change presents no unreviewed safety questions.

Environmental Evaluation The described setpoint change does not affect Plant discharges to the environment and consequently does not present an unreviewed environmental question.

Sinnificant Hazards Determination This proposed LCA modifies the Trojan Technical Specification regarding l

new setpoints for the steam generator low-low level reactor trip and pressurizer low-pressure safety injection. The proposed changes are to Section 2.0, Table 2.2-1 and associated bases, and Section 3.0, Table 3.3-4 of~the Technical Specifications.

Trojan was previously operating on interim conservative setpoints that were established in 1979 due to steam generator reference leg heatup errors and subsequently revised in 1983 due to inaccuracies in the new ITT Barton supplied transmitters. These interim setpoints were determined from the Westinghouse Setpoint Study and information supplied by ITT Barton. The interim setpoints were adjusted downward following trans-mitter replacement during the 1986 outage.

i In accordance with 10 CFR 50.92, the enclosed LCA is judged to involve no significant hazards considerations based on the following:

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1.

The proposed setpoints of the LCA do not significantly increase the probability or consequences of an accident previously evaluated.

The new setpoints for these replacement transmitters accommodate steam generator reference les heatup and LOCA-induced environ-l mental errors not accounted for in the initially licensed set-l points. The primary purpose of the setpoints is to protect the Plant against loss of heat sink (steam generator low-low water level trip) and Loss-of-Coolant Accidents (pressurizer low-pressure safety injection). Previous analyses remain current for l

the new setpoints. The setpoint values have been increased over i

those licensed to provide assurance of reactor protection system actuation prior to exceeding limits established in the safety i

analyses. Thus there is no increase in probability or conse-1 quences of a previously evaluated accident.

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LCA 145 Attachment A Page 4 of 4 2.

This proposed LCA does not create the possibility of a new or different kind of accident from any accident previously evaluated.

The only change to the Plant or its operation is in the sotpoints themselves. The Barton transmitters were replaced with func-tionally equivalent components with less susceptibility to environmental conditions. The adjustment of the setpoints to more restrictive limits does not create the possibility of a new or different kind of accident.

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This propased LCA does not involve a significant reduction in a margin of safety.

The new setpoints improve the margin of safety by incorporating the effect of environmental errors on the indications. None of the setpoints were reduced from those previously licensed and used in the Trojan safety analysis.

Guidance concerning the application of the three standards of 10 CFR 50.92 addressed above is provided by 48 FR 14870 which lists examples that may/may not involve significant hazards considerations. Example 2 of amendments that are considered not likely to involve significant hazards considerations applies to the changes proposed herein and states:

"A change that constitutes an additional limitation, restriction or control not presently included in the technical specifications, es, a more stringent surveillance requirement."

No physical changes in the Plant design or operation are proposed.

The new setpoints provide improved Plant protection by accounting for inaccuracies in indication and thus, provide improved margins.

For these reasons, it is PGE's determination that the proposed change does not involve a significant hazards consideration.

Reference 1.

PCE (B. D. Withers) to NRC (J. B. Martin) letter concerning Barton transmitter setpoint changes dated November 30, 1984.

DRS/ B/kal 5851k

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